Aid station next to an area where people going into the area were camping out. Looks like the cops took a few lessons from the Ukraine and will shut down any centers like that before they become revolutionary strongholds. Security tends to necessarily be pretty porous in those so they most likely did a lot of recon into it and determined the talk was about escalating and sustaining operations longer than the police could. Raids on organizer/instigator safehouses are to be expected. That's why a lot of them had developed the tactic of using aid organizations as cover. It expands into the bathrooms, then the food distribution, then the place to unroll a sleeping bag. Next thing you know, it is going to involve the midnight meetings by the improvised bunk area, then while they are at it, more formalized planning sessions and intelligence hub operations.

That's important to understand in modern conflict, this is becoming a matter of who can learn and implement new tactics ahead of their opposition, and adjusting to the relevant tactics at the intelligence and command level.

This stuff is coming out of the Ukraine. The Maidan was too small to house all of the people who went to Kiev, so a lot took shelter in the aid stations. The medical aid station being in the downstairs part of some larger building, then gradually, the building became a protester stronghold, but was defended mainly by light security and diplomatic understandings.

The Maidan, on the other hand, was an improvised barricade fortress with no pretense of neutrality or noncombatant status. That's the next stage to observe here, and what may have been related to that search or raid for a camp in the woods.

Now personally, for strongholds in major cities, I like high rise parking garages because they are engineered to take major variables in weight and stress and tend to be overbuilt to handle heavy moving vehicles, even car accidents like someone ramming a pillar, and many have helicopter landing pads on the roof. Action film sequences tend to be done in parking garages because they are relatively easy to cordon off and rent, with pyrotechnic action sequences causing no danger to the building. Remember even the first Jihadist attack on the WTC was a car bomb in the parking garage area, which failed to threaten the integrity of the building because that area was already beefed up to handle things like car accidents and fires with nobody missing a day at work.

The issue though, in an intact government situation is that buildings like that can be put under seige and it requires evacuation before you can use it effectively. IE, you don't want someone else having the right to come in and drive through your space in there. What would be interesting is when a shell corporation rents a floor of one as a stronghold, or some group just takes one over.